JPH08221624A - Noncontact ic card system - Google Patents

Abstract

PURPOSE: To provide a noncontact IC card which can maintains the security on a radio line with a ground equipment antenna. CONSTITUTION: As for the noncontact IC card system of toll reception system which allows vehicles to travel on a toll highway on a non-stop and cashless basis, a noncontact IC card 11 consists a ciphering algorithm execution unit for message ciphering and a secret key storage memory for ciphering, and the ground equipment antenna 14 also consists of a ciphering algorithm execution unit and a secret key storage memory for ciphering, and messages sent from both the noncontact IC card 11 and ground equipment antenna 14 are ciphered, key numbers are also sent as the contents of the messages at the same time, and keys for ciphering are updated, message by message, to improve the secrecy of exchanged messages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless IC card system used for toll collection on toll roads. In addition to the above, the present invention can be applied to a field requiring security, such as a physical distribution / entrance / exit management system.

[0002]

2. Description of the Related Art In recent years, as a plan for alleviating traffic congestion on toll roads and saving labor in toll collection work, research into practical use of contactless IC card systems has been actively conducted. FIG. 6 shows an operation message of a non-contact IC card system in recent years. In FIG. 6, reference numeral 11 denotes a non-contact IC card, which is mounted on the vehicle 12 and is a non-contact IC card.
You will enter the toll gate where the card system can be used.

Reference numeral 14 denotes a ground antenna, which is supported by a housing 15. Reference numeral 13 is a wireless communication area with the non-contact IC card created by the ground antenna.

Reference numeral 16 is an antenna control device for controlling the ground antenna. 17 is a toll booth. When the vehicle 12 enters such a toll gate where a non-contact IC card can be used, the non-contact IC card returns unique information to the ground antenna in response to the inquiry message output from the ground antenna. It will be.

This unique information includes important data such as the IC number of the contactless IC card, the vehicle type classification, and the information on the entrance toll gate. The ground antenna and the antenna controller receive the information, and the billing value (toll)
Will be calculated and returned to the contactless IC card.

The contactless IC card receives the charge value, subtracts the charge value from the internal recording medium, and updates the new balance. FIG. 7 shows an internal block diagram of a conventional non-contact IC card. In FIG. 7, 22
Reference numeral 0 is the CPU of the non-contact IC card.

Reference numeral 221 is a program ROM, and 222 is a work or RAM for temporarily storing data. Two
Reference numeral 23 is an EEPROM for electrically storing the amount of money.

Reference numeral 224 is a radio communication logic for converting serial data received for radio communication into parallel data and processing CPU data for radio communication. An analog unit 225 for wireless communication includes a data demodulation circuit and a data modulation circuit.

[0009]

However, in the above-mentioned conventional non-contact IC card, the security on the wireless line between the non-contact IC card and the ground antenna is not considered at all. That is, all inquiry messages, billing messages, and ID messages returned from contactless IC cards were exchanged as messages (plain text) that can be generally recognized by a person with knowledge. .

Such a situation should be a concern in a tollgate system that handles monetary amount information. Because an eavesdropper of this message can easily understand this message, and if it intends, exchanging a part of the message for an advantageous message, it is cheaper than the normal billing value or free. You can also go through the toll gate at. An object of the present invention is to provide a contactless IC card system that can solve these problems.

[0011]

[Means for Solving the Problems]

(First Means) A non-contact IC card system according to the present invention is a non-contact IC card system of a toll collection system capable of non-stop and cashless passage on a toll road, wherein (A) the non-contact IC card is: It is composed of a cryptographic algorithm executor for message encryption and a secret key storage memory for encryption. (B) The ground antenna is also composed of a cryptographic algorithm executor and a secret key storage memory for encryption. By being
(C) A message sent from both the contactless IC card and the onboard antenna is encrypted, (D) The key number is also sent at the same time as the content of the message, and (E) A key for encryption for each message. Is updated to improve the confidentiality of the exchanged messages. (Second Means) A non-contact IC card system according to the present invention is a non-contact IC card system of a toll collection system capable of non-stop and cashless passage on a toll road, wherein (A) the non-contact IC card is: It consists of a cryptographic algorithm executor for message encryption, a secret key storage memory for encryption, and a random number generator. (B) The ground antenna also has a cryptographic algorithm executor and By including a secret key storage memory and a random number generator, (C) a random number generator generates random numbers,
(D) An encryption function is executed by using the random number and a master key arbitrarily selected to create a temporary key, and (E) Calls are made from the temporary key, both the contactless IC card and the ground antenna. Encrypt the message that causes
(F) Furthermore, the selected key number and random number are transmitted at the same time as the contents of the message, and (G) the key and random number for encryption are updated for each message to improve the confidentiality of exchanged messages. It is characterized by

[0012]

[Action]

(Operation of the Invention According to Claim 1) According to the non-contact IC card system of the present invention, a message from the ground antenna is prefixed with a key (hereinafter referred to as Key) number.

The data that follows is encrypted with the confidential Key specified by this Key number. Non-contact IC
Upon receiving this confidential message, the card first recognizes the Key number, searches the Key memory for the confidential Key designated by this Key number, and inputs it to the cryptographic algorithm executor.

By inputting confidential data received at the same time to this cryptographic algorithm executor, a plaintext recognizable message can be obtained as an output. The same applies when the non-contact IC card returns to the ground antenna.

The non-contact IC card arbitrarily selects a secret Key from the Key memory, encrypts the data with the Key, and sends it back to the ground plane together with the Key number which is the index of the Key. (Operation of the invention according to claim 2) According to the non-contact IC card system of the present invention, the key number is added to the head of the message from the ground antenna.

After that, a random number is transmitted for several bytes. Further, the data which follows thereafter is encrypted with the confidential Key designated by this Key number and the temporary Key obtained by executing the random number with the encryption function.

When the confidential message is received, the contactless IC card first recognizes the Key number, and the Key number is recognized.
The confidential Key specified by the y number is searched from the Key memory and input to the cryptographic algorithm executor.

Next, the received random numbers can be input to the cryptographic algorithm executor at the same time, and a temporary Key can be obtained as an output. After that, the temporary key and the confidential data received at the same time are input again to the encryption algorithm executor, whereby a plaintext recognizable message can be obtained as an output.

The same applies when the non-contact IC card returns to the ground antenna. The contactless IC card can be optionally Ke
Select a confidential Key from the y memory, generate a random number, and input it to the encryption algorithm generator.
Create y. The data is encrypted with the Key and returned to the ground plane together with the Key number of the original confidential Key and a random number of several bytes.

[0020]

【Example】

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, 1 is a contactless IC card C
It is PU.

Reference numeral 2 is a ROM for programs. 3 is
It is a working RAM of the CPU and is also a temporary storage area for data.

Reference numeral 4 denotes a non-volatile memory (EEPROM), which is a substitute for a wallet that electrically stores the amount of money when the non-contact IC card is operated in a prepaid form. Reference numeral 5 denotes a key memory, which is an area in which a plurality of encryption keys are stored.

Reference numeral 6 is a cryptographic algorithm executor. Reference numeral 7 is a wireless interface logic circuit, and 8 is a wireless communication unit.

A message communicated to both the non-contact IC card and the ground antenna of the present invention is as shown in FIG. The basic configuration is the Key used for encryption.
One packet is composed of a key number (Key index) 9 pointing to and a set of confidential data 10 encrypted with the Key.

First, the ground plane transmits this packet to the non-contact IC card. The non-contact IC card that receives this first recognizes the Key number. Then, the contents of the Key indicated by this Key number are input to the encryption algorithm executor, and at the same time, the received encrypted message is also input. As the output, plain text recognizable data can be obtained. The operation of reproducing the original plaintext from such encrypted data is called decryption processing.

In other words, if both the antenna control device of the ground plane and the non-contact IC card do not have the same encryption key, the encrypted message cannot be decrypted. This is a very effective means for protecting important data from an external eavesdropper who cannot know the encrypted Key.

The same applies to the case where the non-contact IC card returns to the antenna of the ground plane. First, the non-contact IC card selects an arbitrary Key number, and the K
The contents of the Key memory indicated by ey, that is, the encryption Key
Input y itself to the cryptographic algorithm executor.

At the same time, the message to be transmitted is also input to the cryptographic algorithm executor. As a result, a message encrypted with the confidential Key can be obtained. The operation of encrypting a message from a decipherable plaintext using a confidential Key in this way is called an encryption process.

Then, the arbitrary Key and the encrypted data are packetized and returned to the ground antenna. (Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. 3, 4 and 5.

In FIG. 3, 101 is a CPU of a non-contact IC card. 102 is a ROM for programs. Reference numeral 103 is a work RAM of the CPU, and is also a temporary storage area for data.

Reference numeral 104 denotes a non-volatile memory (EEPRO).
M), which is a substitute for a wallet that electrically stores the amount of money when the contactless IC card is operated in a prepaid form.

Reference numeral 105 denotes a key memory, which is an area in which a plurality of encryption keys are stored. Reference numeral 106 is a cryptographic algorithm executor. 107 is a random number generator.

Reference numeral 108 is a wireless interface logic circuit, and 109 is a wireless communication unit. FIG. 4 shows the temporary key creation process and the data encryption process. As shown in FIG. 4, the contactless IC card first generates a random number by itself.

The random number and a secret key (master key) arbitrarily selected are input to the cryptographic algorithm executor at the same time. As a result, a temporary Key can be obtained.

Next, the temporary Key and the data to be encrypted (encrypted) are input to the encryption algorithm executor at the same time. As a result, encrypted confidential data can be obtained.

The message communicated with both the contactless IC card and the ground antenna of the present invention is as shown in FIG. The basic configuration is the K used for encryption.
Key number (Key index) 12 that points to ey
0, the Key and the temporary Key created by the encryption function with the random number 121, and the temporary Key
A set of confidential data 122 encrypted with y constitutes one packet.

In an actual application, it will be used as follows. First, the ground plane will transmit this packet to the non-contact IC card. The non-contact IC card that receives this first recognizes the Key number.

Then, the contents of the key indicated by this key number are input to the cryptographic algorithm executor, and at the same time, the received random number is also input. A temporary Key can be obtained as its output.

By inputting the temporary Key and the received confidential data into the cryptographic algorithm executor again, plaintext recognizable data can be obtained. The operation of reproducing the original plaintext from such encrypted data is called decryption processing.

That is, if both the antenna control device of the ground plane and the non-contact IC card do not have the same encryption key, the encrypted message cannot be decrypted. This can be a very effective means of protecting important data from an external eavesdropper who cannot know the encrypted Key.

The same applies to the case where the non-contact IC card returns to the antenna of the ground plane. First, the non-contact IC card selects an arbitrary Key number and then the K
The contents of the Key memory indicated by ey, that is, the encryption Key
Input y itself to the cryptographic algorithm executor.

At the same time, the random number generated by the non-contact IC card is also input. As a result, a temporary Key can be obtained, and the message to be transmitted and this temporary Key are input again to the cryptographic algorithm executor.

As a result, a message encrypted with the confidential Key can be obtained. The operation of encrypting a message from a decipherable plaintext using a confidential Key in this way is called an encryption process.

Then, the arbitrary Key, the random number and the encrypted data are packetized and returned to the ground antenna. If the length of the random number to be generated is a plurality of bytes rather than 1 byte, the temporary key to be created is expanded abundantly, and the data security is further improved.

[0045]

Since the present invention is constructed as described above, it has the following effects. (Effect of the Invention According to Claim 1) (1) According to the contactless IC card system of the present invention, the content of the message exchanged with the antenna of the ground plane is encrypted with the confidential Key, so that an eavesdropper can intercept the message. Even if the message can be intercepted in some way, it cannot be decrypted into a valid and meaningful message without knowing the confidential Key. (2) Therefore, it becomes impossible to recognize what part of the message on the wireless line means and what kind of meaning, and by replacing that part, the act of fraudulently defrauding the toll charge, etc. All fraud can be prevented. (3) Further, the most effective usage of the present invention is that the encryption Key, that is, the Key, is set for each message to be communicated.
It is to change the number.

As a result, the encrypted message can be developed in a number of different forms, and the decryption becomes difficult. (Effect of the Invention According to Claim 2) (1) According to the non-contact IC card system of the present invention, the message content exchanged alternately with the ground antenna is encrypted with the confidential Key and the random number. Cage,
Even if an eavesdropper could intercept the message in some way, it would be impossible to decipher it into a valid and meaningful message without knowing the confidential Key. (2) Therefore, it becomes impossible to recognize what part of the message on the wireless line means and what it means, and replace that part to impersonate the toll. , Can prevent any fraud. (3) Further, the most effective usage of the present invention is that the encryption Key, that is, the Key, is set for each message to be communicated.
Change the number and use a random number for temporary Ke
to get y.

As a result, the temporary Key and the encrypted data can be spread innumerably, and the encrypted message can be developed in a number of different forms, making it more difficult to decipher. Become.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a non-contact IC card according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a packet according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a non-contact IC card according to a second embodiment of the present invention.

FIG. 4 is an encryption processing routine according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of a packet according to a second embodiment of the present invention.

FIG. 6 is an operation image diagram of a non-contact IC card.

FIG. 7 is a configuration diagram of a conventional non-contact IC card.

[Explanation of symbols]

 1 ... CPU, 2 ... ROM, 3 ... RAM, 4 ... EEPROM, 5 ... Key memory, 6 ... Cryptographic algorithm executor, 7 ... Wireless interface logic circuit, 8 ... Wireless communication unit, 9 ... Key number, 10 ... Encryption Data ... 11 ... Non-contact IC card, 12 ... Vehicle, 13 ... Wireless communication area created by ground antenna, 14 ... Ground antenna, 15 ... Casing, 16 ... Antenna control device for ground, 17 ... Toll booth, 101 ... CPU, 102 ... ROM, 103 ... RAM, 104 ... EEPROM, 105 ... Key memory, 106 ... Cryptographic algorithm executor, 107 ... Random number generator, 108 ... Wireless interface logic circuit, 109 ... Wireless communication Unit, 113 ... Master Key, 120 ... Key number, 121 ... Random number, 122 ... Encrypted data. 220 ... CPU, 221 ... ROM, 222 ... RAM, 223 ... EEPROM, 224 ... Wireless interface logic circuit, 225 ... Wireless communication unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area G07F 7/08 G08G 1/017 G08G 1/017 G07F 7/08 S

Claims (2)

[Claims] 1. Contactless I of a toll collection system that allows non-stop and cashless traffic on toll motorways
In the C card system, (A) the contactless IC card (11) is composed of a cryptographic algorithm executor (6) for message encryption and a secret key storage memory (5) for encryption. ) Ground plane antenna (14)
(C) Both the contactless IC card (11) and the on-board antenna (14) are constituted by the encryption algorithm executor (6) and the secret key storage memory (5) for encryption. Encrypts messages originating from
(D) The key number (9) is also transmitted as the contents of the message at the same time, and (E) the key for encryption is updated for each message, thereby improving the confidentiality of the exchanged messages. Non-contact IC card system that does. 2. A contactless I toll collection system that allows non-stop and cashless traffic on toll motorways.
In the C card system, (A) the contactless IC card (11) includes a cryptographic algorithm executor (106) for message encryption, a secret key storage memory (105) for encryption, and a random number generator. (107)
(B) The ground antenna (14) also includes a cryptographic algorithm executor (106), a secret key storage memory (105) for encryption, and a random number generator (107). Then, (C) a random number generator (107) is used to generate a random number,
(D) An encryption function is executed by using the random number and the arbitrarily selected master key (113) to create a temporary key, and (E) the temporary key, the non-contact IC card (11) and the ground plane. The message sent from both antennas (14) is encrypted, and (F) the selected key number and random number are sent at the same time as the contents of the message.
(G) A contactless IC card system characterized by improving the confidentiality of exchanged messages by updating a key for encryption and a random number for each message.